In the related art, a projected capacitive touch panel is known as an input device for an electronic device such as a computer or a portable information terminal.
This projected capacitive touch panel incorporates therein a large number of X-axis electrodes extending in a predetermined direction (hereinbelow, referred to as an X-axis direction) and a large number of Y-axis electrodes extending in a direction perpendicular (hereinbelow, referred to as a Y-axis direction) to the predetermined direction. Moreover, the X-axis electrodes and the Y-axis electrodes are arranged in a matrix, and a controller is connected to each of the X-axis electrodes and each of the Y-axis electrodes. Then, the touch panel has a structure where when a user operates the touch panel with a finger or the like, a capacitance value between each electrode and the finger or the like is detected to specify an operation position of the user.
Now, a touch panel that uses thin metal wire made of, for example, gold for the X-axis electrodes and the Y-axis electrodes is known in order to use the touch panel, for example, in a display device with a large screen (for example, Patent Documents 1, 2).
In this touch panel that uses the thin metal wire, a substrate is patterned by laminating a metal layer such as gold thereon to form a large number of lines of fine thin metal wire on the substrate.
An example of this touch panel that uses the thin metal wire includes a touch panel in which two substrates on each of which a large number of lines of thin metal wire are arranged parallel to each other are made, and these substrates are stacked one on another to form the above X-axis electrodes and the above Y-axis electrodes.
In this touch panel using the thin metal wire, a large number of wiring lines are formed of the thin metal wire in parallel. Thus, it is possible to reduce resistance of the wiring lines, and the touch panel can be used suitably, for example, in a display device with a large screen. Moreover, in this touch panel, peripheral wiring lines can be formed of the same material as that of the thin metal wire, and the peripheral wiring lines and the thin metal wire can be formed on the same plane at once. Thus, it also becomes possible to reduce manufacturing steps.
Now, a display surface of a common display device is provided with a pixel part that includes sub-pixels of red (R), green (G), and blue (B) and a black matrix in a grid-like form that partitions the sub-pixels.
In the above touch panel, the thin metal wire is laid in a grid-like form in the X-axis direction and the Y-axis direction. Thus, when this touch panel is placed on the display surface of the display device, the thin metal wire overlaps the pixel part which displays color information, and the thin metal wire shields light from the sub-pixel parts. That is, in this touch panel, since a part of the pixel part is blocked by the thin metal wire and an aperture ratio of the pixel part is reduced, there is a problem of a reduction in luminance of the display device. Moreover, since the thin metal wire having a regular repeated shape and the black matrix also having a regular repeated shape overlap each other obliquely in a planar manner, periodic intersecting parts are generated in the thin metal wire and the black matrix, and the periodically-generated intersecting regions shield light from the pixel part. Thus, there is a problem of generation of moire and deterioration in quality.
Thus, Patent Document 1 proposes an approach to improving invisibility of the thin metal wire and preventing reduction in luminance of the display device by forming the thin metal wire so as to have a width narrower than the width of the black matrix, and by arranging the thin metal wire so as to overlap the black matrix. In addition to the above, there are Patent Documents 3, 4 as documents that describe the related art to the present invention.